Circuit for electric discharge



June 27, 1944. Y J. H. CAMPBELL 22503 CIRCUIT FOR ELECTRIC DISCHARGE DEVICES Original Filed Oct. 5, .1959

. F i 21. v

/5 L /6 I /Z\ 49 L I I /I' g /7 /4. A4 /3 4 l Inventor: John HCampbell,

X His Attorney.

I prising Reissued June 27, 1944 v UNITED STATE 22,503 cuwmr ron sneer-mo mscmca a DEVICES John H. Campbell, Cleveland Heights, (Dhio, assignor to General Electric Company, a corporation of New York Original No. 2,266,619, dated December 16, 1941,

Serial No. 298,082, October 5, 1939.- Application for reissue August 2'7,

9' Claims.

' gether with'operation at high efilciencies. An-

other object is to provide a simplified circuit;

arrangement which permits operation of the devices directly from ordinary commercial sources (115 volts, for example) of either alternating or direct current. Further objects and advantages of my invention will appear from the following description of species thereof and from the drawing.

In the drawing, Fig. l is a diagrammatic representation of a circuit arrangement comprising my invention; Fig. 2 is a perspective view of aportion. or a novel combination thermal switch and ballasting device which may, if desired, be employed in the circuit; and Figs. 3, 4 and 5 are diagrammatic representations of modified circuit 1942, Serial No.

arrangements included within the scope of the present invention.

Referring to Fig.' 1, the circuit illustrated therein comprises a plurality (two, in this instance) of gaseous electric discharge devices l0, l0 electrically connected in series with each other and with a ballast resistance ll across the terminals l2, l3 of a source of alternating or direct current. The devices Ill, l0 may be positive column discharge lamp devices comthe elongated tubular envelopes or containers M, it having sealed into the ends thereof the thermionic electrodes l5, l6, li'plB' each herein illustrated as consisting of a coil (preferably a coiled-coil of wire such as tungsten coated with a material of high electron emissivity, such as an alkaline earth oxide like barium or strontium oxide or mixtures thereof) If desired the said electrodes may be so designed that the voltage drop thereacross exceeds the ionizing voltage of the gaseous atmosphere so that a local arc discharge is formed thereacross during starting, as disclosed in Patent 2,103,034, G. E. lumen. The envelopes i4, it contain a gaseous atmosphere such as a rare gas like neon or argon, or mixtures thereof. or a vaporizable metal such as mercury, or a, mixture of gas and vaporizable metal. If desired,

' l1, H which may ballast resistance II was a watt, volt tungsten bimetallic type fully each of the devices l0, l0 may be a low-pressure positive column lamp of the fluorescent type recently made commercially available wherein the envelope is coated internally with a suitable luminescent material and contains a filling of rare gas, preferably argon, at a low pressure of the order of l -IO mm, of Hg, preferably about 4 mm., and a small quantity of mercury. The ballast resistance ll may, as illustrated, consist of an incandescent tungsten filament lamp.

In accordance with my invention, the lamps Ill, iii are initially shunted by the switches be of any suitable type, either manually or automatically operable and when the. lamp electrodes becomes sufliciently heated the switches I1 and H are opened one after the other whereby the necessary starting voltage is applied to each lamp. Several automatically operable switches are well known to the art, as exemplified, for example, by bimetallic switches and ma et c vibrator switches commercially available at the present time for use with the above-referred-tofluorescent lamps.

The following is a detailed description of an arrangement operated in accordance with the showing in Fig, 1:

Each of the lamps I0," lil' was a fluorescent lamp oi the type referred to above comprising an envelope about eighteen inches long and one and one-half inches 'in diameter, containing argon at a pressure of about 4 mm., and a small quantity of mercury. The electrodes consisted of coiled-coils of tungsten wire coated with a mixture of barium and strontium oxides. The standard commercial filament incandescent lamp. The switches l1, H were of the thermal described in application Serial No. 228,365, filed September 3, 1938, by Leo R. Peters and assigned to the assignee of the present application, the heaters for the switches being in series with lamp II. The current source i2, It was a commercial H5 volt, 60 cycle alternating current line.

In the operation of the circuit, when voltage is applied to the line the two switches l1, H are closed and current fiows through the oathodes of both lamps thereby heating them, the said cathodes and ballast lamp H all being connected in series across the line terminals l2, l3, as will be apparent from an inspection of Fig. 1.

For convenience in explaining the operation, let

it be assumed that switch ll opens first. When said switch I! opens, the current flowing through the seriescircuit is suddenly reduced to zero absorbed by the two lamps iii limo-o is I holiest; and with a limo vol I lamps during operotion do moi; 2i

and with it the voltage drop across the ballast lamp H likewise reduces. Thus; the full line voltage is applied to lamp: m causing an arc discharge to strike therein between its .e1ccate a plurality of lamps whose combined sieriioo voltages are greatly in excess of the line voltage, whereas a. similar circuit employing a single lamo whose starting voltage was higher than the llo.

iii? greater than ooe hali mill ma'fioi i ii o'cooioi" than the percentage of tho line vol oloooi'hoo'i by the ballast. Thus with o to i the, combined. lamp volioge is or maizeiy 82% of the line voltage leov matoly 18% of the line volilo o 1 1'.- l by the ballast; with a line combined lamp voltage is El or M 75% of the line voltage loo 25% of the line voltage as hinecl lamp voltage is ill of the line voltage, loo. of the line voltage as moi; liisi.

The voltage drop across silo, iii

ually increases as the lino iol" all iii. 100 line volts, the tote-.1 f oo v s. M5

The lamps will no image: moiiicoioooi eraci-on at line voltage below i at; 100 volts. Thus, boiloeiii. oioizoinoci wlth'this oircuiijwith a oliii'eionco ll lime and lamp volts of only five cool.

It will be obvious that more chm coo o may be operated on this oiroiiii, ii: tors being lamp and lino .volio. Zia io of course, ihetihe combined coil:

sonrcevoltaoc. However, in i: cally illustrated ohovc, iziio each oi. the lamps lo olloiilii pending to :9. 1mm emeni. iigooo ofivontooe of! this oii'cois. voltage oi each loitoo Jim voltage, the oomhinecl oioi considerably higher (in iiio as high). Thus; ii is wool hull; or envelopo (not .sho

0 El, 22. to elements lo, iii ifoooeciiively, of switch.

ocrooo the cathodes of Tho operation of the Fig. oontoioioe ii ifltio'hollost, and ii is trodes 45, Hi, and the current through the sir- 5 voltage would be inoperative. cult momentarily increases clue to the negative In place of thermal switches of the type disresistance oo'efllcient of the lamp w. This action closed in the abovementionecl Peters application, further raises the temperature of the electrodes glow-type thermal switches of the time disclose l5, l6 of lamp Ill and effectively reduces its in applichtion Serial No. 289,891 filed August 12, required starting voltage. Thus when switch 21$ 1939, by W. C. Smitley, maybe emoloyed. In H opens, the lamp ill starts, in this C%@.-8i3$ this'case one of the swifiches is shunted by c. approximately 60 per cent oi its normal sterling high resistance (2,000 ohms, for example) since voltage. .(This explanation also holds ior the switch contacts are normoily open. To docurreni: operation.) With both lamps lo anii plicate the results given alcove, c. '55 wait lamp Ill operating, the lamp ll eels as a. ballast to 15 is used at H.

limit. the current flowing in the circuit cm In Fig. 2 is shown a combined swiici'i and bol the line voltage is low, the resistance of the last unit which may be emploveo; in the Fig. 1 ballast lamp ii is automatically decreased and circuit to combine in one smell mil: inhoswitches as the voltage rises, the resistance increases l1 and IT and the ballast ll. of the thus affording an automatic xegilloiaion of our g g switches ll, i1 comprises a iiooliooie pair of rent over wide volioge ranges, V bimetallic strips ii, iii and iii", iii ltosoectivel r, The followin-gioosohle of meosm'omenilc when the curved strips so, ill loeiog ooiizofioo bye; during oporction oi the above ice-mm: single heeter or filament ii whiclsi ooz soeoonlic 1m iii: o ls; iiil. iii;

Fromihe above table it llicit with to the ballast lamp ll of oio. The cwiioheo my invention the perceniosgo of the voiiloo'o gig ll, 81', as illustrated, ore o Gil-o closed. and claimed. in i. ii 2243.365, filed September 3, mo. and oosied to the ossioiooe :ollcoiion. The sold him owl w, l9 and homer i gloss stem 2c, and are sec iifiion i log Loo c.

ae wesooi:

from o x l oo iii-cool iii with o. colli chic gas, such as helium oil; email orefose ooly carrying o hose (not siioml, oooh as Woo employed on 'rcclio having six mono contests: iliaxeon. eoislvc promo one comiecteli by cooolocooro iii, 24 lo oleyoenio so, 5% resoecilvciy. oi owilzoh conductors ill; one! by oonoocioro 2 3 iii oooooiio coils of ihe hooiei' ii. The ooooooiliom lo chic case are the some co those sho o lo That the conclucioro M, ill to ooiizeh E o oooioeoioii loom W; the coo. cincioro iii, 23' to switch {W ooooecieo oorooo lilo coihoolcs iii, ill of ioooo Gil; Ellie oonooo= tom 28, to heater ii oooolooizeo-heizweeirl aloe ieiminol l2 and coihoolo iii of the lamp ii'l.

iiiovlcc shown in Fig. 2 ooecicely cs ciescriho imvfig I Eloeilevioo shown in 2i ii moms possible more lomoo loom one iio iauloe, ii oocioic on i oi? oliiveois oument, ii ocsiirco loci-oi lioco'lise oosisioooo os ocii'oiiisogeo oi iawo oiz'oiiiiio ohoomi ciiono which oooo oi oiioiii insertion of an inductance or choke coil 26 in series with lamps in and III in addition to the ballast resistance or lamp II. The source l2, I3 may, as in Fig. 1, be alternating or direct current. The purpose of the inductance 25 is to provide a partial ballast of the lamps which efie'ctively reduces the watts loss over a pure resistance ballast as shown in Fig. 1. Such an addition oi reactance to the circuit may be necessary in the operation of some discharge lamps and will improve the current and voltage wave shapes.

In the Fig- 4 circuit, designed for operation from a'source l2, 13 of alternating current, inductance 25 is substituted as the ballast for resistance H of Fig. 1', and resistances or lamps 26,

2B are inserted in series with the switches H, 1.1 respectively, across lamps i and i0. In some cases where the line voltage is'considerably higher than 115 volts, as for example 220 volts, and the cathodes 15, I6 are of the same resistance as those in the Fig. 1 lamps, it will be necessary to place such resistances '26 and 28' in series with the switches to control the flow of current during the starting cycle. Alter the lamps in and II) have started, switches l1 and H are open and the resistances 26 and 28' are out of the circuit. The ballast need not be a single choke as shown at 25, but may be a pure resistance or lamp ballast as shown in Fig. 1, or a combination of the two as in Fig. 3.

The Fig. circuit is like that shown in Fig. 1 except that inductances or choke coils 21, 21' are inserted in series with the switches l1, l1, re-

spectively, across lamps I0 and III. This arrangement is particularly eiTective where the starting voltages of the lamps I0 and Ill are higher than those of the lamps in Fig. 1, the choke coils serving to produce a voltage surge when the switches l1 and I1 are opened so as to start the lamps. This circuit is alsoeflective for starting a single lamp H! or III whose starting voltage ishigher than that of either lamp ID or III oi Fig. 1, but whose operating voltage is about the same as the combined operating vo1t ages of lamps Ill and Ill of'Fig. 1.

While I have shown and described above certain forms of my invention, it will be obvious to those skilled in the art that various changes may be made therein without departing from the spirit of the present invention. If desired, the directly heated electrodes I5, Ii may be replaced by indirectly heated electrodes wherein the said coils IS, IS serve as heaters for a surrounding metal (nickel) tube which is electrically connected at one end to one end of the said heater, and is coated with electron emissive, material. Moreover, for operation from a source of direct current, only one of the electrodes l5 or IE need be a thermionic electrode;

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, a plurality of gaseous eiec-- tric discharge devices having therein spaced electrodes, one electrode at least in each device being thermionic and adapted to be heated by the passage of current therethrough prior to the starting of the device, ballasting means having a positive nonlinear resistance temperature characteristic and having low heat inertia, means connecting said devices and ballasting means in a series circuit, and a time delay starting switch for each of said devices each switch being connected across one of said devices and in series with the thermionic electrode thereof, and means for causing said switches to open successively.

2. In combination a plurality of gaseous electric discharge lamps each having an electrode at each end thereof adapted to be heated by the.passage of current therethrough prior to the starting of a discharge in the lamp, ballasting means comprising'a resistor having a positive nonlinear resistance temperature characteristic and having low heat inertia, means connecting said ballasting means and said lamps in a series circuit, a plurality of starting switches one for each of said lamps each switch being connected across its respective lamp and in series with the electrodes thereof, and means by which said switches are opened in succession and with a time delay after the energization of said circuit. I

3. In combination a plurality of gaseous electric discharge lamps each having an electrode at each end thereof adapted to be heated by the passage of current therethrough prior to the starting of a discharge in the lamp, ballastlng means comprising a tungsten filament incandescent lamp, means connecting said ballasting means and said lamps in a series circuit, a plurality of starting switches one for each of said lamps each switch being connected across its respective lamp and in series with the electrodes thereof, and means by which said switches are opened in succession and'with a time delay after the energization of said circuit.

4. In combination, a plurality of electric discharge devices having therein spaced electrodes adapted to be heated by the passage or current therethrough prior to the starting of the device. ballast for-said devices, means connecting said ballast and said electrodes in a series circuit, and a starting switch having a pluralityof pairs a: contacts, each pair being connected to interrupt said series circuit between the electrodes of a separate device, said switch having common operating means for said pairs of contacts constructed to operate them in sequence.

5. In combination, a plurality of electric discharge devices having therein spaced electrodes adapted to be heated by the passage of current therethrough prior to the starting of the device, a ball-asting resistor, means connecting said resistor, said devices and the electrodes thereof in a series circuit, and a multiple switch having one pair of contacts connected to interrupt said series circuit between the electrodes of one device, and having another pair of contacts connected to interrupt said series circuit between the elec- 6. In combination, a plurality of electric discharge devices having therein spaced electrodes, one electrode at least of each device being thermionic and adapted to be heated by the flow of current therethrough prior to the starting of the device, a ballast, means for connecting said devices and said ballast in series across a source of current supply, a plurality of starting switches each connected to shunt one of said devices and to control the flow of current through the thermionic electrode thereof, the sum of the arc-drop voltages of said devices being materially greater than one-half of the voltage of said source, and means operative to open saidswitches successively.

'7. In combination, a plurality of electric discharge devices having therein spaced electrodes adapted to be heated by the flow of current therethrough prior to the starting of the devices, a ballast, means for connecting said devices and said ballast in series across a source of current supply, a plurality of starting switches each connected to shunt one of said devices and. to control the flow of current through the electrodes thereof, the sum of the arc-drop voltages of said devices being of the order of 75% of the value of the voltage supplied by said source, and means operative toopensaid switches successively.

8. In combination, a plurality of electric discharge devices having therein spaced ,elmtrodes adapted to be heated by the flow of current therethrough prior to the starting of the devices, a ballast, means for connecting said devices and said ballast in series across a source of current supply, a plurality of starting switches each conby said devices being at least twice the percentage of the source voltage absorbed by said ballast,

and means operative to open said switches successively. 1

9. In combination, a plurality of electric discharge devices having therein spaced electrodes adapted to be heated by the flow of current therethrough prior to the starting of the devices, a. ballast including reactive means, means for connecting, said devices and said ballast in series across a source of current supply, a plurality oi. starting switches each connected to shunt one of said devices and to control the flow of current 

